Hi Paul, as for me I could successfully run KolibriOS in QEMU/i440fx 4MB with coreboot and SeaBIOS. Here's my sequence of actions:
git clone https://review.coreboot.org/coreboot/ cd ./coreboot/ make crossgcc-i386 run a csb_patcher script from https://review.coreboot.org/c/coreboot/+/33509 , mainly for the SeaBIOS multiple floppies patch and to auto-download the floppy collection make menuconfig , then choose QEMU/i440fx and 4 MB (0x00400000 CBFS size) make ./csb_patcher.sh flop add all the floppies that you'd like, then run a command qemu-system-x86_64 -L . -m 256 -vga vmware -net nic,model=rtl8139 -net user -soundhw ac97 -usb -usbdevice tablet -bios ./build/coreflop.rom -serial stdio
As you see I'm not using KVM - that's because I don't have this kernel module installed on a PC I'm at the moment. I believe your problem is related to the QEMU flags - please start with my set of flags which is more-or-less guaranteed to work, and slowly change one-by-one to your liking. For your testing purposes,
Here's my coreflop image - https://www.sendspace.com/file/j4idzp , sha256 sums 68bfb64a68e37df0e8939391ee70aef41c7cd03d8de624b2a6d836d7e1ac8d55 ./coreflop.tar.gz dec8577a76bf190c72f69a4b7fe4f8ef53d53af19ac6890485311da7dd6eb2d5 ./coreflop.rom coreboot revision - b77cf2299c516a7f5a9a4eccad2b21157278a283
You may also play with the other floppies inside if you'd like - it's fun!